Bladder irrigation with tap water to reduce antibiotic use for urinary tract infections in catheter users

Authors: Stefan den Hoedt, Felice E.E. van Veen, Jeroen R. Scheepe, Bertil F.M. Blok

Abstract

Objective

To evaluate the safety and effectiveness of bladder irrigation (BI) with tap water to reduce antibiotic use for the treatment of urinary tract infections (UTIs) in patients with recurrent UTI symptoms and to assess the treatment satisfaction of BI.

Patients and Methods

This prospective, observational study included patients with an indwelling catheter or performing clean intermittent catheterisation (CIC) who had recurrent UTI symptoms between July 2022 and March 2024. BI with tap water was used for the treatment of UTIs without systemic symptoms (e.g., fever, flank pain or delirium). Patients started daily irrigation at the onset of UTI symptoms and used a tapering schedule. The number of antibiotic treatments for UTIs, UTI incidence rate ratio (IRR), UTI‐related hospitalisations, treatment satisfaction and quality of life (QoL) were compared between a 3‐month period before and after BI with tap water.

Results

A total of 60 patients were included with a median (interquartile range) age of 64.5 (50.4–72.6) years, 66.7% were male, and 83.3% were performing CIC. Antibiotic use was decreased on average by 38.1% (IRR = 0.62; P = 0.016) and catheter‐associated UTIs by 37.9% (IRR = 0.62; P = 0.005). No increase was observed in the incidence of UTIs with systemic symptoms or UTI‐related hospitalisations. In addition, no differences were observed in the health‐related QoL. The majority of patients were positive about the subjective effectiveness (81%), ease of use (86%) and overall satisfaction (85%) of BI with tap water.

Conclusion

These findings emphasise the potential of BI with tap water as a promising and patient‐friendly alternative for the treatment of UTIs in patients with urinary catheters. BI with tap water significantly reduces antibiotic use and UTI incidence in patients with recurrent UTIs and is a safe and patient‐friendly alternative that can be easily implemented in the management of UTIs.

Introduction

Among patients performing clean intermittent catheterisation (CIC) or with an indwelling catheter (IDC) UTIs are a common complication, with estimated annual incidence rates of up to 45% [1] and 57% [2], respectively. UTIs in patients with urinary catheters should be treated with antibiotics, as recommended by the European Association of Urology guidelines on Urological Infections [3]. Treatment of asymptomatic bacteriuria (i.e., only symptoms of cloudy or foul‐smelling urine) has no benefit in patients with urinary catheters [3, 4]. However, healthcare providers often confuse asymptomatic bacteriuria with UTI, resulting in unnecessary antibiotic use leading to increased antibiotic resistance in patients with urinary catheters. Recently, a Swiss study found that pathogens causing catheter‐associated UTIs (CAUTIs) are more often resistant to empirical antibiotics than non‐CAUTI pathogens [5]. One of the primary implications of antibiotic resistance in UTIs is the potential for limited treatment options. When bacteria develop resistance to empirical antibiotics, it becomes challenging to effectively treat complicated UTIs, leading to prolonged illness, increased healthcare costs, and mortality [6]. Considering the global burden of antibiotic resistant micro‐organisms [7], it is necessary to explore alternative treatments for UTIs in patients with urinary catheters.

Bladder irrigation (BI) with tap water has been proposed as a potential safe, efficient, cost‐effective and patient‐friendly alternative for preventing and treating UTIs in patients performing CIC or with an IDC [8, 9]. Despite its off label use in several hospitals in the Netherlands [9], evidence supporting its safety and effectiveness in reducing antibiotic use by preventing and treating UTIs is currently lacking. Recently, a cross‐sectional study reported good satisfaction and subjective improvement outcomes in patients performing BI with tap water [9]. Based on these results, it is essential to gather evidence on the safety and effectiveness of BI with tap water in reducing the use of antibiotics without increasing the risk of developing a UTI with systemic symptoms. In this study, we aimed to prospectively evaluate patient‐reported outcomes on safety and effectiveness of BI with tap water to reduce antibiotic use for UTIs in patients performing CIC or with an IDC in the community setting. Additionally, we studied quality of life (QoL) and treatment satisfaction of BI with tap water. We hypothesised that BI with tap water would reduce antibiotic use for UTIs without increasing the risk of UTIs with systemic symptoms. We also expected it to result in high treatment satisfaction and improve generic QoL.

Patients and Methods

Study Design

We performed a single‐centre, prospective, observational study between July 2022 and March 2024 at the department of Urology in the Erasmus Medical Center, Rotterdam, the Netherlands. Patients who started with BI with tap water for the treatment of UTIs were included. The primary outcome measure was the number of antibiotic treatments for UTIs. Secondary outcomes included UTI incidence, UTI‐related hospitalisations, treatment satisfaction and health‐related QoL. Outcome measures were assessed using (validated) questionnaires at two time at the end of a 3‐month period before BI initiation (baseline, retrospective) and at the end of a 3‐month period after BI initiation (follow‐up, prospective; Fig. 1).

An uncomplicated UTI was defined as an acute onset of one or more of the following cloudy or foul‐smelling urine, haematuria, dysuria/pain during catheterisation, urinary incontinence, urinary frequency, urinary urgency, and suprapubic pain. If only complaints of cloudy or foul‐smelling urine were present, no UTI was recorded. Although a urine test (e.g., a urine culture, sediment or dipslide) is generally recommended to confirm a UTI, this was not a requirement in our study. Patients could start with BI immediately upon recognising the onset symptoms of a UTI, considering that bacteriuria is common in this specific patient population. A urine test was performed if antibiotics were needed.

This study was approved by the local Medical Ethical Review Committee (registration EMC‐2021‐0855). Participants provided digital informed consent. Data were handled confidentially according to the Dutch General Data Protection Regulation and the results [10]. The study was retrospectively registered in the International Standard Randomised Controlled Trial Number (ISRCTN) registry (ISRCTN16005365).

Study Population

Eligible patients were aged ≥18 years and performed CIC or had a transurethral or suprapubic IDC. In addition, patients had to start BI with tap water due to recurrent UTIs. Patients with two or more UTI episodes within the last 6 months were eligible. Patients were not included if they received BI with tap water solely for other reasons, such as prevention of catheter blockage or bladder stones, or treatment of haematuria, as were patients with a history of surgical bladder reconstruction. Patients were asked to participate on the day they received BI instructions, either at the outpatient clinic or by telephone, and were asked to complete the first questionnaire (baseline) within a week after receiving BI instructions and the second questionnaire after 3 months follow‐up (Fig. 1).

For patients with recurrent UTIs, we first assessed whether treatment should be optimised for neurogenic lower urinary tract dysfunction (NLUTD) or non‐NLTUD (e.g., increase CIC frequency, antimuscarinics, mirabegron, intradetrusor botulinum neurotoxin type A [BoNT‐A] injections). Bladder stones were excluded via ultrasonography. Patients were offered behavioural modification strategies. If recurrent UTIs persisted, BI with tap water was initiated. Other non‐antibiotic treatments for UTIs, such as cranberries, d‐mannose, phytotherapy, intravesical glycosaminoglycans or methenamine hippurate were not prescribed. If BI proved ineffective, antibiotic prophylaxis was initiated. In some cases, patients were already on antibiotic prophylaxis prior to BI, often prescribed by the referring hospital.

Bladder Irrigation Procedure

Bladder irrigation with tap water was prescribed to patients with recurrent UTIs and was used for the treatment of UTIs without systemic symptoms (e.g., fever, flank pain or delirium). The non‐systemic UTI symptoms cloudy or foul‐smelling urine, haematuria, dysuria/pain during catheterisation, urinary incontinence, urinary frequency, urinary urgency, and suprapubic pain. Patients received BI instructions from our continence nurses at the outpatient clinic. They were instructed to start BI at the onset of UTI symptoms, using it as a treatment rather than a preventive measure.

For the BI procedure, a 50‐mL catheter‐tip syringe was used, which was filled with fresh tap water from a clean, non‐sterile container. The bladder was actively irrigated by flushing in and drawing back on the plunger to potentially reduce the concentration of the bacterial load in the bladder. This process involved patients emptying each returned syringe of fluid directly into a second non‐sterile container and then continuing to irrigate with fresh 50 mL volumes until the outgoing solution was clear. Patients were instructed to perform irrigation gently, as increased pressure from flushing or suction from drawing back on the plunger may cause pain or trauma to the bladder. If suction of the bladder wall occurred, patients were advised to fill the bladder with an additional 100 mL of water and retain it during irrigation. Tap water at body temperature was preferred to prevent bladder cramps. The syringe was discarded within 24 h after first use.

Patients followed a tapering schedule starting with daily BI during the first week, followed by a gradual reduction in frequency to every other day, twice a week, once a week, and thereafter stopping BI. They were instructed to reduce the frequency when the effluent from the first syringe was clear. Daily BI was resumed if UTI symptoms recurred. Patients were instructed to contact their physician and discontinue BI in the presence of systemic symptoms. Antibiotics were prescribed when BI was not feasible, did not sufficiently relieve UTI symptoms or in cases of a UTI with systemic symptoms.

Data Collection

A combination of self‐developed and validated questionnaires were conducted at baseline and after a period of 3 months (follow‐up) in data management platform Castor EDC.

At both questionnaire assessments, we evaluated the number of self‐reported antibiotic treatments for UTIs within the 3 months prior to questionnaire completion. We also recorded the number of episodes with UTI‐related complaints, differentiating between cases with and without systemic symptoms (e.g., fever, flank pain, delirium), during that period. Additionally, we assessed hospitalisations that resulted from a UTI. The EuroQoL‐five Dimensions‐five Levels (EQ‐5D‐5L) [11, 12] was used to measure generic health‐related QoL. Treatment satisfaction was assessed with the nine‐item Treatment Satisfaction Questionnaire for Medication (TSQM‐9) [13]. The abbreviated version comprises of three (subjective) effectiveness, convenience and global satisfaction. Patients’ medical charts were reviewed to compile the following sex, age, type of urinary catheter, aetiology of catheterisation (NLUTD or non‐NLUTD), underlying neurogenic aetiology, treatment for (non‐)NLUTD (e.g., antimuscarinics, mirabegron, intradetrusor BoNT‐A injections, sacral neuromodulation), antibiotic prophylaxis use, and immunosuppressant use.

Statistical Analysis

We analysed antibiotic use, and UTI rates between baseline and follow‐up with negative binomial regression instead of Poisson regression to account for over‐dispersion, which produced incidence rate ratios (IRRs) with 95% CIs. An intention‐to‐treat analysis was utilised, meaning that patients who stopped BI during the follow‐up period were included in the final analysis as well. To determine the appropriate sample size, we used the mean number of antibiotic uses from a previous study [9], with an expected 30% reduction after starting with BI with tap water. After adding baseline data from the first 30 patients and using a Poisson rates formula for sample size calculation, we found that we would need at least 58 patients for an 80% power level at a 2.5% one‐sided significance level. Descriptive statistics were calculated to describe baseline and BI characteristics. Analyses were performed with R software, version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria).

Results

Patient Characteristics

A total of 82 patients were identified as eligible between July 2022 and November 2023; 67 (82%) patients completed the baseline questionnaire and 60 (73%) the follow‐up questionnaire (Fig. 2). All patients performed BI within the follow‐up period and were therefore included in the analysis. Patient and BI characteristics are described in Tables 1 and 2. Of the 60 patients included, 33% were female, 47% had NLUTD and 83% were performing CIC. The median (interquartile range) age was 64.5 (50.4–72.6) years. In all, 13 (22%) patients discontinued BI during the 3‐month follow‐up for which patients could have multiple reasons. Six patients discontinued because they no longer experienced UTI symptoms, four patients received other treatments during follow‐up (e.g., IDC, oxybutynin BI or intradetrusor BoNT‐A), two patients experienced no improvement in UTI symptoms, two patients experienced discomfort/pain as a result of BI, and one patient found BI not feasible.

Urinary Tract Infections and Antibiotic Use

Table 3 displays patient‐reported antibiotic use and UTIs in the 3‐month period before and 3 months after starting with BI. Prior to the introduction of BI, 83% of patients had received one or more antibiotic treatments for a UTI in the preceding 3 months, with an average number of 1.97 treatments per patient. At 3‐month follow‐up, 53% of patients received antibiotics for a UTI, with a mean number of 1.22 treatments per patient. Subsequently, there was a 38% reduction observed in the number of antibiotic treatments (IRR 0.62, 95% CI 0.42–0.91; P = 0.016). Additionally, there was a statistically significant reduction of 38% observed in the number of self‐reported UTIs (IRR 0.62, 95% CI 0.45–0.86; P = 0.005). There were no differences in the number of UTI‐related hospitalisations before and after treatment (18% vs 12%, respectively, P = 0.443).

Treatment Satisfaction and QoL

The TSQM‐9 was completed by 58 of 60 patients, as two patients only partially completed the questionnaire. The outcomes are shown in Fig. 3 and show that the majority of patients had a positive view toward subjective effectiveness, ease of use and overall satisfaction. In all, 85% (49/58) reported being at least somewhat satisfied with tap water BI. EQ‐5D‐5L outcomes, in particular the index score and EuroQol‐visual analogue scale (EQ‐VAS), are summarised in Table 4. No significant differences were observed between baseline and follow‐up in either index score (0.64 vs 0.66; P = 0.793) or EQ‐VAS (65.6 vs 65.4; P = 0.963).

Discussion

The results of this prospective study demonstrated that the introduction of BI with tap water in patients with recurrent UTI symptoms resulted in a significant reduction of 38% in antibiotic use and 38% in the incidence rate of UTIs. In addition, BI with tap water was considered well tolerated in terms of subjective effectiveness, ease of use and global satisfaction with the treatment. No significant gain or loss was observed in generic QoL.

Antimicrobial resistance poses a major global threat to healthcare and public health [14]. Patient populations that are prescribed a relatively large number of antibiotics, such as patients with urinary catheters, face an elevated risk of developing antibiotic resistant bacteria. Alternatives to antibiotics have been studied numerously, particularly preventive agents, such as probiotics, small compounds, nutraceuticals, and even vaccines [15, 16]. Promising preliminary results were described, but large‐scale randomised trials demonstrated that D‐mannose or cranberry capsules were not efficacious in preventing the recurrence of UTIs [17, 18]. In addition, the costs and sustainability of prescribed or over‐the‐counter non‐antibiotic alternatives could be an issue when implementing on a large scale. Nowadays, prescribing environmentally conscious therapies is encouraged to make healthcare sustainable [19]. BI with tap water can be a preventive and therapeutic treatment that can sustainably reduce the need for antibiotics in the treatment of UTIs. Tap water is widely available, making it easy to use and implement worldwide. In the Netherlands, tap water is of high quality and continuously monitored for microbiological agents [20, 21]. However, this is not the case in every country. In such cases, tap water can easily be replaced by bottled drinking water or boiled water. The gain in costs and healthcare availability for both options would still be substantially compared to antibiotics or irrigation with saline.

In terms of safety, the composition of tap water in Europe is generally considered safe for drinking. A study analysed 579 tap water samples from across Europe for >60 parameters, assessing compliance with the European Union and international drinking water regulations [22]. Most parameters demonstrated high compliance rates >99%. Minerals (e.g., calcium, magnesium), disinfectants (e.g., chlorine), and other chemicals (e.g., nitrates, heavy metals) were present in low and acceptable concentrations [22], suggesting minimal risk of adverse effects on the bladder from these constituents. However, the potential long‐term risks associated with BI using tap water remain unstudied, further research is necessary to fully understand its safety implications over extended periods of use.

To date, limited research has been performed on the efficacy of BI for the treatment of UTIs. A Cochrane review from 2017 evaluated different BI regimens in patients with a long‐term IDC and found inconclusive evidence regarding the acceptability, complications, and efficacy in preventing UTIs [23]. Most of the included studies were generally underpowered and of poor methodological quality [23]. A randomised controlled trial with 60 comatose patients showed a significant decrease in urine colony‐forming units, white blood cell counts and body temperature in patients receiving daily BI with 450 mL normal saline compared to the control group receiving routine catheter care [24]. In addition, a retrospective study of 28 children with bladder augmentation showed that daily to monthly BI with normal saline resulted in no recurrent UTIs during a median follow‐up of 48 months [25]. Similarly, a prospective study of patients with spina bifida and bladder augmentation demostrated that daily BI with 240 mL of saline significantly reduced the incidence of UTIs over a 10‐year period [26].

The use of tap water as irrigation solution instead of saline has only been reported in four previous studies. In three studies, tap water was used as an irrigation solution to prevent bladder calculi in augmented bladders, to irrigate continent catheterisable ileal pouches, and to dilute Solution G for BI, without resulting in an increased risk of UTIs [8, 27, 28]. BI with tap water for the prevention and treatment of UTIs and other catheter‐related complications was first studied in 2022 in a single‐centre cross‐sectional study [9]. In that study, less than half of all reported UTIs were treated with antibiotics. We hypothesised based on those findings that BI could decrease antibiotic use without increasing the incidence of UTIs. Similar results were found in the present study; 56% of UTIs were treated with antibiotics in the 3 months preceding the introduction of BI and 56% at the 3‐month follow‐up. Therefore, the proportion of UTIs treated with antibiotics before and during BI remained constant, suggesting that the observed reduction in antibiotic use was due to a decrease in the number of UTIs. This implies that BI may have a preventive effect rather than merely being used as a treatment when symptoms are present. A plausible explanation for our findings is that the extensive duration of the tapering schedule might have had a preventive effect against UTIs. Alternatively, some patients may have continued daily BI as a preventive measure, despite being instructed to follow a tapering schedule within the study.

In accordance with the findings of the recent cross‐sectional study conducted in our clinic [9], the vast majority of patients reported good satisfaction results with BI. A limitation of the previous study was the exclusion of patients who were not using BI at the moment of data collection but had used in the past. Patients that discontinued due to discontent with the treatment modality were therefore not included in the cross‐sectional study but were captured in the present prospective study. Utilising the validated TSQM‐9 for satisfaction outcomes brings several advantages as well, as it captures not only global satisfaction, but also the subjective effectiveness of BI on treating UTIs, as well the convenience with BI. Particularly, convenience of tap water BI was addressed previously in a study of patients with an ileal pouch [8]. In that cross‐over trial, tap water BI was described as more economical, less complicated in handling and less time‐consuming than irrigations with saline.

Our study also examined the impact of BI on generic QoL. While BI with tap water effectively reduces UTIs and could be expected to positively influence QoL, no significant changes were observed in QoL as measured by the EQ‐5D‐5L. This questionnaire provides a comprehensive assessment of QoL across various dimensions, including mobility, self‐care, usual activities, pain/discomfort, and anxiety/depression [11, 12]. Although reducing UTIs may decrease discomfort and anxiety associated with recurrent infections, these improvements may not be substantial enough to significantly affect EQ‐5D‐5L scores. This suggests that either the improvement in QoL requires a longer period to become noticeable, or that other factors influencing overall well‐being were not sufficiently addressed by the intervention.

The discontinuation rate of BI with tap water was 22% during the 3‐month follow‐up. A substantial proportion discontinued BI due to resolution of UTI symptoms, which is a positive outcome. These patients can start BI in case of recurrent symptoms. However, 7% discontinued due to lack of efficacy or adverse events (pain/discomfort during BI). Bladder cramps and discomfort are a potential concern during active BI. Adjusting the rate and/or amount of fluid injection can reduce this risk, as indicated during BI instructions. Nevertheless, some patients may still experience discomfort during this procedure. No serious adverse events were reported. In addition, one patient found BI infeasible and 15% of BIs were performed by relatives or home care, indicating that some patients may require assistance due to limitations in self‐administration capability. However, BI with tap water allows most patients to manage UTI symptoms independently. Initiating BI at the onset of symptoms can provide timely relief and help prevent potential complications.

This study is the first to our knowledge to prospectively evaluate the safety and effectiveness of BI with tap water for the treatment of UTIs. Nevertheless, our main conclusions are based on patient‐reported data, which pose the risk of recall bias or inaccuracies in response due to different interpretations of the survey questions. We attempted to overcome this potential problem by providing examples of how to interpret the question and by implementing identical questions in both the baseline and follow‐up questionnaire. Moreover, the participants were asked to define their perception of a UTI to ensure it met the criteria of a UTI. However, the potential recall bias associated with the retrospective evaluation of UTI episodes and antibiotic use remains a limitation, which may lead to an under‐ or overestimation of UTIs during the comparison period. Furthermore, the limited follow‐up period and the uncontrolled nature of the study make it challenging to draw valid conclusions regarding the efficacy of prevention or treatment of UTIs with respect to antibiotic use. Still, this prospective series indicates that BI is effective in reducing antibiotic use, providing a promising base for future research on BI efficacy and treatment satisfaction. Prospective randomised studies with longer follow‐up are needed in order to confirm the efficacy of BI with tap water for the treatment of UTIs.

Conclusions

In the midst of the challenges posed by antibiotic resistance, our findings emphasise the potential of BI with tap water (or bottled water depending on local conditions) as an effective and patient‐friendly alternative for the treatment of UTIs. BI with tap water significantly reduces antibiotic use and UTI incidence in patients with recurrent UTI symptoms. Implementing this safe and patient‐friendly alternative not only reduces reliance on antibiotics, but also provides a pragmatic solution that can be easily integrated into clinical practice, improving patient care and aligning with sustainable healthcare practices.

Conflict of Interests

The authors declare no conflicts of interest.

Funding

None.